The present invention relates to an ingredient that adds vegetable protein and/or phytochemicals to leavened and unleavened food products.
Soy products are known to have constituents of high nutritional value. One constituent is protein. The Food and Drug Administration, FDA, has recently proposed that food products containing 6.25 grams of soy protein per Reference Amount Customarily Consumed (RACC), that are low in fat and low in cholesterol as well, may carry a health claim. The FDA has proposed that 4 servings of 6.25 grams of soy protein per day (25 grams total) as a part of a low fat, low cholesterol diet may reduce the risk of coronary heart disease.
Soy also contains phytochemicals such as isoflavones, also referred to as phytoestrogens that have been associated with many positive health benefits. These health benefits include preventing hormone-dependent cancers and substantially eliminating symptoms such as hot flashes in peri- and post-menopausal women as well as reducing the risk of osteoporosis. Soy flour has been reported to have isoflavone concentrations ranging from about 1 mg/g to about 3 mg/g of soy flour. Isoflavone levels in soy flour generally exceed those in other soy products, such as soy protein concentrates and isolates. Soy flour is also a good source of dietary fiber, minerals and B vitamins.
Despite their nutritional benefits, soy products have had only limited use in foods typically consumed in the United States because incorporation of soy products has produced deleterious effects on the organoleptic and textural properties of many types of foods. For example, soy-fortified bread, containing a high concentration of soy protein, typically exhibits undesirable characteristics such as diminished loaf volume, poor crumb grain, an uneven, “bumpy” crust and a flavor that is bitter or “beany”. A soy-fortified unleavened food typically has a dough that is sticky and that has a poor machinability. A soy-fortified dried dough, such as pasta is also soft and mealy in texture when cooked. These undesirable food properties have occurred with the use of soy flour, soy isolates and soy concentrates.
Patents such as the Mehltretter et al., U.S. Pat. No. 3,949,093, which issued Apr. 6, 1976, describe an incorporation of additives into a bread dough prior to baking in order to render the dough more amenable to receiving a higher protein concentration. In particular, the Mehltretter et al. patent describes adding to a dough, an ester of a fatty acid containing twelve to eighteen carbon atoms and polyoxyethylene ether of a propylene glycol glycoside containing one to two moles of combined fatty acid per mole and 5 to 20 moles of combined ethylene oxide per mole.
Foods that have a structure which is based upon components of wheat flour rely, in some manner, on the action of gluten, which is a component of the wheat flour. Gluten is a mixture of proteins present in wheat and in other cereal grains. Gluten is naturally occurring in wheat flour and is advantageous in making leavened products such as bread because it has an elastic, cohesive nature which permits it to retain carbon dioxide bubbles generated by leavening agents, and therefore to form a uniform air cell structure that defines the bread.
Wheat flour has historically contained about 10% to 12% protein by weight of the flour. More recently, gluten levels in some wheat grown in the United States have dropped to a concentration that does not support acceptable air cell formation in yeast leavened dough. As a consequence, some wheat flour produced in the United States is supplemented with wheat gluten that is added to wheat flour in order to elevate the gluten to levels of about 10% to 12%. Gluten represents about 90% of the protein content of wheat flour. The protein composition of wheat gluten comprises gliadin in a concentration of about 39.1% by weight; glutenin in a concentration of about 35.1% by weight; and globulin in a concentration of about 6.75% by weight.
Attempts have been made to prepare baked products such as bread with soy flour and soy milk. These attempts have included an addition of gluten in a soy-based dough in a proportion that is equivalent to the proportion of gluten in wheat flour, referred to herein as a “natural ratio.” Breads produced with the proportion of gluten to soy were very dense and had a more coarse texture and had a non-uniform air cell network.